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United States Patent |
6,241,532
|
Howell
|
June 5, 2001
|
High density electrical connector assembly and connector for use therewith
Abstract
A high density electrical connector assembly comprising first and second
sheet-like bodies. The first sheet-like body is made from an insulating
material and has a surface and a plurality of electrical traces extending
to a plurality of first interconnect pads disposed on the surface in a
first pattern. The second sheet-like body is also made from an insulating
material and has a surface and a plurality of second electrical traces
extending to a plurality of second interconnect pads disposed on the
surface of the second sheet-like body in a second pattern. The second
pattern is substantially a mirror image of the first pattern. The surface
of the first sheetlike body faces the surface of the second sheet-like
body so that the first interconnect pads face the second interconnect
pads. A flexible sheet of an insulating and compliant material is disposed
between the first and second interconnect pads and has first and second
opposite surfaces. A plurality of first connector pads is disposed on the
first surface in the first pattern and a plurality of second connector
pads is disposed on the second surface in the second pattern and
electrically connected through the flexible sheet to the first connector
pads. A Clamping assembly is mountable to the first and second sheet-like
bodies for urging the first and second sheet-like bodies and the flexible
sheet together so that the first interconnect pads register with and
engage the first connector pads and the second interconnect pads register
with and engage the second connector pads. The compliant material of the
flexible sheet facilitates electrical connections between the first
interconnect pads and the first connector pads and between the second
interconnect pads and the second connector pads for making electrical
connections between the first and second interconnect pads.
Inventors:
|
Howell; Robert P. (San Jose, CA)
|
Assignee:
|
Exatron, Inc. (San Jose, CA)
|
Appl. No.:
|
344644 |
Filed:
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June 25, 1999 |
Current U.S. Class: |
439/67; 439/66 |
Intern'l Class: |
H01R 009/09 |
Field of Search: |
439/67,66
|
References Cited
U.S. Patent Documents
4548451 | Oct., 1985 | Benarr et al. | 339/17.
|
5691041 | Nov., 1997 | Frankeny et al. | 428/209.
|
5795162 | Aug., 1998 | Lambert | 439/63.
|
Primary Examiner: Donovan; Lincoln
Assistant Examiner: Le; Thanh-Tam
Attorney, Agent or Firm: Flehr Hohbach Test Albritton & Herbert LLP
Claims
What is claimed is:
1. A high density electrical connector assembly comprising a first
sheet-like body of an insulating material having a surface and a plurality
of electrical traces extending to a plurality of first interconnect pads
disposed on the surface in a first pattern, a second sheet-like body of an
insulating material having a surface and a plurality of second electrical
traces extending to a plurality of second interconnect pads disposed on
the surface of the second sheet-like body in a second pattern, the second
pattern being substantially a mirror image of the first pattern, the
surface of the first sheet-like body facing the surface of the second
sheet-like body so that the first interconnect pads face the second
interconnect pads, a flexible sheet of an insulating and compliant
material disposed between the first and second interconnect pads and
having first and second opposite planar surfaces, a plurality of first
connector pads disposed on the first planar surface in the first pattern
and a plurality of second connector pads disposed on the second planar
surface in the second pattern and electrically connected through the
flexible sheet to the first connector pads and clamping means mountable to
the first and second sheet-like bodies for urging the first and second
sheet-like bodies and the flexible sheet together so that the first
interconnect pads register with and engage the first connector pads and
the second interconnect pads register with and engage the second connector
pads whereby the compliant material of the flexible sheet facilitates
electrical connections between the first interconnect pads and the first
connector pads and between the second interconnect pads and the second
connector pads for making electrical connections between the first and
second interconnect pads.
2. A connector assembly as in claim 1 wherein the flexible sheet has a
plurality of first connector pads arranged in rows and columns and having
a separation pitch of approximately 0.050 inch or less.
3. A connector assembly as in claim 2 wherein the plurality of first
connector pads have a separation pitch of approximately 0.016 inch or
less.
4. A connector assembly as in claim 2 wherein the plurality of first
connector pads have a separation pitch of approximately 0.003 inch or
less.
5. A connector assembly as in claim 1 wherein the flexible sheet is a layer
of plastic having a constant thickness ranging from 0.001 to 0.002 inch.
6. A connector assembly as in claim 5 wherein the flexible sheet is made
from a polyimide film.
7. A connector assembly as in claim 1 wherein the first connector pads on
the first planar surface of the flexible sheet are aligned with respective
second connector pads on the second planar surface of the flexible sheet.
8. A connector assembly as in claim 1 wherein the first pattern of the
first interconnect pads is offset with respect to the second pattern of
the second interconnect pads and wherein the first connector pads on the
first planar surface of the flexible sheet are offset with respect to
respective second connector pads on the second planar surface of the
flexible sheet, the flexible sheet being cantilevered between respective
first and second interconnect pads for further facilitating electrical
connections between the first and second interconnect pads.
9. A connector assembly as in claim 8 wherein the second connector pads
have respective diameters and wherein the first connector pads are offset
with respect to respective second connector pads by an amount at least
equal to the respective diameters so that the first connector pads are
pivotable by the flexible sheet relative to respective second connector
pads for enhancing electrical connections between respective first and
second interconnect pads.
10. A connector assembly as in claim 1 wherein the first sheet-like body is
a rigid printed circuit board and the second sheet-like body is a flexible
printed circuit board.
11. A connector assembly as in claim 1 wherein the first and second
sheet-like bodies are each flexible printed circuit boards.
12. A connector assembly as in claim 1 wherein the second sheet-like body
is a flexible printed circuit board and wherein the clamping means
includes a first clamp having a first planar clamping surface at least as
large as the first pattern and a layer of an elastomeric material disposed
between the first clamping surface and the second sheet-like body for
facilitating electrical connections between the first and second
interconnect pads and the first and second connector pads.
13. A high density electrical connector for use with a first sheet-like
body of an insulating material having a surface and a plurality of first
interconnect pads disposed on the surface in a first pattern and a second
sheet-like body of an insulating material having a surface and a plurality
of second interconnect pads disposed on the surface of the second
sheet-like body in a second pattern that is substantially a mirror image
of the first pattern comprising a flexible sheet of an insulating and
compliant material having first and second opposite surfaces, a plurality
of first planar connector pads disposed on the first surface in the first
pattern and a plurality of second planar connector pads disposed on the
second surface in the second pattern, the first and second planar
connector pads being electrically connected through the flexible sheet and
the first pattern of the first connector pads being offset relative to the
second pattern of the second connector pads, whereby the flexible sheet is
adapted for disposition between the first and second sheet-like bodies so
that the first interconnect pads register with and engage the first planar
connector pads and the second interconnect pads register with and engage
the second planar connector pads, the flexible sheet being cantilevered
between respective first and second connector pads for facilitating
electrical connections between the first and second interconnect pads.
14. A connector as in claim 13 wherein the flexible sheet has a plurality
of first planar connector pads arranged in rows and columns and having a
separation pitch of approximately 0.050 inch or less and a plurality of
second planar connector pads arranged in rows and columns and having a
separation pitch of approximately 0.050 inch or less.
15. A connector as in claim 13 wherein each of the first planar connector
pads has a diameter of approximately 0.025 inch or less.
16. A connector as in claim 15 wherein each of the first planar connector
pads includes a layer of a conductive material and a layer of particle
interconnect material disposed on the layer of the conductive material.
Description
This invention pertains to electrical connector assemblies and, more
particularly, to high density electrical connector assemblies.
Apparatus and methods for electrically connecting first and printed circuit
boards, first and second flexible cables and a flexible cable to a printed
circuit board have heretofore been provided. In one such apparatus and
method for connecting a first printed circuit board to a second printed
circuit board or a flexible cable, each of the traces of the first printed
circuit board are electrically connected to a pin which extends through a
corresponding bore in the second printed circuit board or flexible cable
to electrically connect by soldering to a trace of the second printed
circuit board or flexible cable. Unfortunately, the size of such pin
connectors limit the density of electrical connections per unit area of
the first printed circuit board. In addition, the pin connectors are
easily damaged by bending or breaking and the printed circuit board itself
is susceptible to damage during the soldering process. Furthermore, such
soldering is not advantageous when a temporary electrical connection is
desired.
In another such apparatus and method, a layer of a rubber material having a
plurality of electrically conductive wire-like elements extending
perpendicular to the first and second planar surfaces of the rubber layer
is disposed between a plurality of first interconnect pads of a first
printed circuit board and a plurality of second interconnect pads of a
second printed circuit board arranged in a pattern corresponding to the
first interconnect pads. In a similar apparatus, a matrix of small metal
balls suspended in a layer of rubber is provided. A clamp sandwiches the
rubber layer between the first and second printed circuit boards. The
plurality of wire-like elements or stacking ball-type elements extending
between a respective pair of first and second aligned interconnect pads
serves to electrically connect such first and second interconnect pads.
Unfortunately, the rubber layer requires that significant clamping forces
be applied to the first and second printed circuit boards to ensure an
electrical connection between the plurality of first and second
interconnect pads.
In general, it is an object of the present invention to provide a high
density electrical connector assembly that has a small footprint.
Another object of the invention is to provide a high density electrical
connector assembly of the above character that does not utilize soldered
connections.
Additional objects and features of the invention will appear from the
following description from which the preferred embodiments are set forth
in detail in conjunction with the accompanying drawings.
FIG. 1 is an isometric view of a high density electrical connector assembly
of the present invention.
FIG. 2 is an exploded view of the high density electrical connector
assembly of FIG. 1.
FIG. 3 is an exploded cross-sectional view of the high density electrical
connector assembly of FIG. 1 taken along the line 3--3 of FIG. 1.
FIG. 4 is a plan view of a connector for use with the high density
electrical connector assembly of FIG. 1.
FIG. 5 is a cross-sectional view of a portion of the connector of FIG. 4
taken along the line 5--5 of FIG. 4 with a portion of the high density
electrical connector assembly of FIG. 1 shown in phantom lines therein.
FIG. 6 is a top plan view of the connector of FIG. 4 taken along the line
6--6 of FIG. 5.
FIG. 7 is a plan view of a portion of another embodiment of a connector for
use in a high density electrical connector assembly of the present
invention.
FIG. 8 is a cross-sectional view of a portion of the connector of FIG. 7
taken along the line 8--8 of FIG. 7.
FIG. 9 is a top plan view of the connector of FIG. 7 taken along the line
9--9 of FIG. 8.
In general, a high density electrical connector assembly comprising first
and second sheet-like bodies is provided. The first sheet-like body is
made from an insulating material and has a surface and a plurality of
electrical traces extending to a plurality of first interconnect pads
disposed on the surface in a first pattern. The second sheet-like body is
also made from an insulating material and has a surface and a plurality of
second electrical traces extending to a plurality of second interconnect
pads disposed on the surface of the second sheet-like body in a second
pattern. The second pattern is substantially a mirror image of the first
pattern. The surface of the first sheet-like body faces the surface of the
second sheet-like body so that the first interconnect pads face the second
interconnect pads. A flexible sheet of an insulating and compliant
material is disposed between the first and second interconnect pads and
has first and second opposite surfaces. A plurality of first connector
pads is disposed on the first surface in the first pattern and a plurality
of second connector pads is disposed on the second surface in the second
pattern and electrically connected through the flexible sheet to the first
connector pads. Clamping means is mountable to the first and second
sheet-like bodies for urging the first and second sheet-like bodies and
the flexible sheet together so that the first interconnect pads register
with and engage the first connector pads and the second interconnect pads
register with and engage the second connector pads. The compliant material
ofthe flexible sheet facilitates electrical connections between the first
interconnect pads and the first connector pads and between the second
interconnect pads and the second connector pads for making electrical
connections between the first and second interconnect pads.
More in particular, the high density electrical connector assembly 21 of
the present invention includes a first printed circuit board in the form
of rigid printed circuit board 22 having a sheet-like body or substrate in
the form of planar body 23 (see FIGS. 1-3). The planar body 23 is made
from any suitable insulating material such as fiberglass or other rigid
printed circuit boards material commonly known to the industry and has a
first or top surface 24 and a parallel second or bottom surface 25. The
thickness between surfaces 24 and 25 ranges from approximately 0.015 to
0.125 inch. A plurality of electrical traces 26 extend along planar body
23 to a plurality of first interconnect pads 27. The electrical traces 26
can be formed on either or both of surfaces 24 and 25 or, alternatively,
can be formed on an internal surface of planar body 23 so as to be
partially or totally inside printed circuit board 22. Each of the
electrical traces 26 terminates at one of its ends at one of the first
interconnect pads 27 disposed on one of surfaces 24 or 25. In the
illustrated embodiment of connector assembly 21, first interconnect pads
27 are disposed on top surface 24 adjacent one of the edges of the printed
circuit board 22. For simplicity, the electrical traces 26 are shown only
in FIG. 2 where only several of such traces are shown on top surface 24. A
conventional edge connector 28 is further provided on board 22.
Four groups 29 of interconnect pads 27 are provided on top surface 24, as
shown most clearly in FIG. 2. First interconnect pads 27 are shown in FIG.
2 as being of equal diameter and shape, however interconnect pads 27 of
varying sizes and shapes can be provided. Each of first interconnect pads
27 is disk-like in shape and made from any suitable conductive material
such as copper. Pads 27 have a suitable diameter, such as approximately
0.025 inch. First interconnect pads 27 of each group 29 are disposed in
any suitable pattern 31. In one preferred embodiment of connector assembly
21, each pattern 31 consists of a grid of interconnect pads 27 arranged in
four rows and twenty-five columns.
The separation pitch between each row and each column in pattern 31 is
approximately 0.050 inch or less, although smaller pitches as low as 0.003
inch or less with vapor deposition printed circuit board techniques or
0.016 inch with standard printed circuit board electroplating, masking and
etching techniques can be provided. The preferred pitch will vary in these
ranges as a function of the specific application. Connector assembly 21
can have greater than or less than the four groups 29 and the groups 29
can have other patterns 31 and any number of first interconnect pads 27.
Connector assembly 21 further includes a second printed circuit board in
the form of flexible printed circuit cable 34 having a first sheet-like
body or substrate in the form of flexible sheet 35 (see FIGS. 1-3). The
flexible sheet 35 is made from any suitable insulating material such as a
polyimide film such as Kapton manufactured by E.I. duPont de Nemours and
Company of DuPont Road, Circleville, Ohio 43113. Sheet 35 is formed with a
first or top surface 36 and an opposite second or bottom surface 37 and
has a thickness between surfaces 36 and 37 of approximately 0.002 inch. A
plurality of second electrical traces 38 are formed on one or both of
surfaces 36 and 37 by any suitable means such as any conventional printed
circuit board manufacturing process including electroplating, masking,
etching and vapor deposition. In the illustrated embodiment, second
electrical traces 38 are formed on both surfaces 36 and 37 although, for
simplicity, only several of second electrical traces 38 are shown on top
surface 36 in FIGS. 1 and 2. Each of the second electrical traces 38
extends from a first interconnect pad 41 provided at one end of flex cable
34 to a second interconnect pad 42 provided at the other end ofthe
flexible cable. Second interconnect pads 38 on flexible cable 34 are
formed on bottom surface 37 and are shown in phantom in FIG. 2. The second
interconnect pads 42 are similar in composition and construction to first
interconnect pads 27 and preferably each of the second interconnect pads
42 has a size and shape in plan which is substantially identical to the
size and shape of the respective first interconnect pad 27 on rigid
printed circuit board 22.
Second interconnect pads 42 are arranged on flexible cable 34 in at least
one group and as shown are arranged in a plurality of four groups 43. Each
group of second interconnect pads 42 is arranged in a pattern 44 that is a
mirror image of the pattern 31 of the respective group 29 on rigid printed
circuit board 22. In the illustrated embodiment of connector assembly 21,
pattern 44 is substantially identical to pattern 31 and consists of a grid
formed with four rows and twenty-five columns. The separation pitch
between each row and column in pattern 44 is the same as the corresponding
separation pitch in pattern 31.
A connector or cable interposer 51, shown in plan in FIG. 4, is included
within connector assembly 21 and is formed from a flexible sheet 52 made
from any suitable insulating and compliant material such as plastic. A
preferred material for flexible sheet 52 is a polyimide film such as the
polyimide film sold under the trademark KAPTON Flexible sheet 52 is formed
with a first or top planar surface 53 and an opposite second or bottom
planar surface 54 and has a thickness between surfaces 53 and 54 ranging
from 0.001 to 0.002 inch. A plurality of first planar connector pads 56
are formed on top surface 53 and a plurality of second planar connector
pads 57 are formed on bottom surface 54. Connector pads 56 and 57 are each
formed by any suitable means, such as any conventional printed circuit
board manufacturing process including electroplating, masking, etching and
vapor deposition, and are each made from any suitable conductive material
such as a layer of 0.5 ounce copper having a thickness of approximately
0.0075 inch. Connector pads 56 and 57 further include a layer of gold
plate that has a thickness of approximately 0.000020 inch and is deposited
on top of the copper layer. An optional layer of particle interconnect
material 58 of the type described in any of U.S. Pat. Nos. 4,804,132,
5,083,697, 5,334,809, 5,430,614, 5,471,151, 5,506,514, 5,565,280,
5,634,265, 5,642,055 and 5,670,251, the entire contents of which are
incorporated herein by this reference, is disposed atop the gold plate
layer.
First connector pads 56 are adapted for engagement with first interconnect
pads 41. In this regard, the plurality of first connector pads 56 on top
surface 53 are arranged in a plurality of groups 61 corresponding in
number and configuration to groups 29 of first interconnect pads 27. More
specifically, the first connector pads 56 in each group 61 are arranged in
a pattern 62 that is a mirror image of pattern 31 of first interconnect
pads 27. First connector pads 56 in each pattern 62 preferably have a size
and shape corresponding to the size and shape of the respective first
interconnect pads 27 of pattern 31. The horizontal and vertical separation
pitch of first connector pads 56 thus corresponds to the horizontal and
vertical separation pitch of first interconnect pads 27 discussed above.
Second connector pads 57 are similarly arranged on bottom surface 54 in a
plurality of groups corresponding in number to groups 43 of second
interconnect pads 42. Each of second connector pads 57 is aligned, as
shown in FIG. 5, with the respective first connector pad 56 on top surface
53. As such, the second connector pads 57 in each group are arranged in a
pattern that is a mirror image of pattern 62 of first connector pads 56.
Means is included within high density cable interposer 51 for electrically
connecting respective first and second connector pads 56 and 57. In one
preferred embodiment of interposer 51, said electrical connection means
includes a via 66 which extends through flexible sheet 52 and is connected
at one end to the first connector pad 56 and at the other end to the
second connector pad 57 (see FIGS. 5 and 6).
Connector assembly 21 has clamping means 71 carried by at least one of
rigid printed circuit board 22 and flexible cable 34 for securing together
printed circuit board 22, cable interposer 51 and flexible cable 34.
Clamping means 71 includes a first elongate clamp 72 mountable to rigid
printed circuit board 22 and a second elongate clamp 73 mountable to
flexible printed circuit cable 34. First and second clamps 72 and 73 are
similar in size, shape and construction and, in this regard, are each made
from any suitable material such as aluminum. First clamp 72 is formed with
a planar surface 76 having a size and shape preferably at least as large
as the profile in plan of the plurality of first interconnect pads 27 on
rigid printed circuit board 22. Second clamp 73 has a similar planar
surface 77 which has a size and shape at least as large as the profile in
plan of the second interconnect pads 42 of flexible printed circuit cable
34.
A plurality of fasteners in the form of bolts 78 are included in clamping
means 71 for securing together the first and second clamps 72 and 73.
First clamp 72, rotated 180.degree. about its longitudinal axis in FIG. 2
so as to show planar surface 76 thereof, is provided with a plurality of
bores 81 for receiving bolts 78. Second clamp 73 has an equal plurality of
bores 82 for threadably receiving the threaded ends of bolts 78. A
plurality of bores 83, 84 and 86 are respectively provided in planar body
23, flexible sheet 52 and flexible sheet 35 for permitting the passage of
bolts 78 through rigid printed circuit board 22, cable interposer 51 and
flexible cable 34. First and second reinforcing rings 88 are attached to
respective top and bottom surfaces 24 and 25 of planar body 23 for each of
bores 83 to reinforce the planar body 23 about the bore 83. Each of the
reinforcing rings 88 extends around the opening of the respective bore 83
and is formed on surface 24 by any suitable means such as any conventional
printed circuit board manufacturing process including electroplating,
masking, etching and vapor deposition. Similar reinforcing rings 91 are
provided on top and bottom surfaces 53 and 54 of flexible sheet 82 for
each of bores 84 and similar reinforcing rings 92 are formed on the top
and bottom surfaces 36 and 37 of flexible sheet 35 for each of bores 86.
Clamping means 71 includes means for registering rigid printed circuit
board 22 relative to cable interposer 51 so as to cause first interconnect
pads 27 to register with respective first connector pads 56 and means for
registering flexible printed circuit cable 34 relative to the cable
interposer 51 so as to cause second interconnect pads 42 to register with
second connector pads 57. Such registration means includes bolts 78 and
bores 83, 84 and 86 and further includes a plurality of rigid pins 96
preferably formed from the material of second clamp 73 and extending
perpendicularly of planar surface 77 adjacent bores 82. First clamp 72 is
provided with an equal plurality of holes 97 extending through planar
surface 76 for receiving the ends of registration pins 96. A plurality of
holes 101-103 are respectively provided in planar body 23, flexible sheet
52 and flexible sheet 35 for receiving registration pins 96 when the rigid
printed circuit board 22, the cable interposer 51 and the flexible printed
circuit cable 34 are properly aligned relative to each other.
A layer of an elastomeric material is optionally disposed between first
clamping surface 76 and 30 cable interposer 51 for facilitating electrical
connections between first interconnect pads 27 and first connector pads 56
and between second interconnect pads 42 and second connector pads 57. In
the illustrated embodiment of connector assembly 21, such layer is in the
form a plurality of pads 106 made from any suitable material such as
silicone rubber or Sarcon from Fujipoly America Corp., 365 Carnegie
Avenue, Kenilworth, New Jersey 07033. Pads 106 are secured to planar
surface 76 of the first clamp 72 between bores 81 by any suitable means
such as an adhesive. Each of the pads 106 engages top surface 36 of
flexible sheet 35 behind a group 43 of second interconnect pads 42. As
such, each of pads 106 has a size and shape at least as large as pattern
44 of the second interconnect pads 42. Pads 106 can have a thickness
ranging from 0:020 to 0.100 inch and preferably approximately 0.020 inch.
In operation and use, connector assembly 21 is assembled by positioning
cable interposer 51 between rigid printed circuit board 22 and flexible
printed circuit cable 34 so that first interconnect pads 27 register with
and engage first connector pads 56 and second interconnect pads 42
register with and engage second connector pads 57. More specifically,
assembly 21 can be sequentially pieced together on second clamp 73 by
aligning holes 101 in planar body 23 with registration pins 96 so as to
mount rigid printed circuit board 22 to second clamp 73, next aligning
holes 52 in flexible sheet 52 with the registration pins 96 so as to mount
cable interposer 51 to the second clamp and lastly aligning holes 103 in
flexible sheet 35 with the registration pins so as to mount flexible
printed circuit cable 34 to the second clamp. First clamp 72 is pressed
against top surface 23 of flexible sheet 25 and aligned so that holes 97
in the first clamp register with pins 96 in the second clamp. Bolts 78 are
subsequently introduced through bores 81 in first clamp 72 and threadably
secured within bores 82 of second clamp 73. When so assembled, first and
second clamps 72 and 73 serve to urge rigid printed circuit board 22 and
flexible printed circuit cable 34 together. Top surface 24 of rigid
printed circuit board 22 faces bottom surface 37 of flexible printed
circuit cable 34 so that first interconnect pads 27 face second
interconnect pads 42, separated by first and second connector pads 56 and
57 of cable interposer 51.
The compliant material of flexible sheet 52 disposed between the plurality
of first and second interconnect pads 27 and 42, facilitates an electrical
connection between interconnect pads 27 and 42 and the respective
plurality of connector pads 56 and 57. Specifically, flexible sheet 52 can
bend where necessary to accommodate any irregularities in the thicknesses
of planar body 23 of rigid printed circuit board 22 and flexible sheet 35
of flexible printed. circuit cable 34 and similarly any irregularities in
the thicknesses of first and second interconnect pads 27 and 42. The layer
of particle interconnect material 58 provided on each of first and second
connector pads 56 and 57 further facilitates the electrical connections
between the connector pads 56 and 57 and the respective interconnect pads
27 and 42.
The electrical connections resulting from high density electrical connector
assembly 21 occupy a relatively small footprint. Cable interposer 51 is
relatively simple in construction and can be easily manufactured by any
conventional printed circuit board manufacturing process including
electroplating, masking, etching and vapor deposition. As discussed above,
the configuration of electrical connections and the size and shape of
respective interconnect and connector pads can be easily varied as
desired. Connector assembly 21 can be disassembled and reassembled as
needed with confidence that repeatable electrical connections between
first and second interconnect pads 27 and 42 are being made. In addition,
cable interposer 51 is reusable.
Although connector assembly 21 has been shown and described as having only
first and second flexible or rigid printed circuit boards, it should be
appreciated that more than two such boards can be included in a connector
assembly of the present invention. For example, an additional plurality of
interconnect pads can be provided on bottom surface 25 of rigid printed
circuit board 22 opposite first interconnect pads 27 and electrically
coupled to a second flexible printed circuit cable similar to cable 34 by
means of an additional cable interposer similar to cable interposer 51. A
single stack consisting of a circuit board, an interposer, a second
circuit board, a second interposer and a third circuit board sandwiched
between first and second clamps 72 and 73 can be provided in such an
assembly. Alternatively, an additional set of interconnect pads can be
provided on rigid printed circuit board 22 and offset from groups 29 of
first interconnect pads 27 and an additional set of clamps 72 and 73
utilized for forming a second connector assembly. It should be further
appreciated that cable interposer 51 can be used with any combination of
rigid or flexible printed circuit boards.
The high density electrical connector of the present invention can have
other embodiments for enhancing electrical connections between
interconnect pads of first and second flexible or rigid printed circuit
boards. For example, a portion of a high density electrical connector
assembly 109 is shown in FIG. 8 and includes a high density electrical
connector or cable interposer 111, a portion of which is shown in FIG. 7,
that has similarities to cable interposer 51. Like reference numerals have
been used to describe like components of cable interposers 51 and 111.
Flexible sheet 52 of cable interposer 111 has a plurality of first
connector pads 112 that are substantially similar to first connector pads
56 and are disposed on top surface 53 of the flexible sheet. In the
illustrated embodiment of connector assembly 109, the plurality of first
connector pads 112 are arranged in four groups 113 with the connectors
pads 112 in each group 113 being arranged in a pattern 116 which is
substantially identical to pattern 62. Each of first connector pads 112 is
offset with respect to the respective second connector pad 57 and, as
such, the pattern of first connector pads 112 is offset with respect to
the pattern of second connector pads 57. More specifically, each of the
fist connector pads 112 is offset with respect to the respective second
connector pad 57 by an amount at least equal to the diameter of such
second connector pad 57. An electrical trace 117 preferably made from the
same copper material utilized in first connector pads 112 extends from the
first connector pad 112 to a position overlying the respective second
connector pad 57. A via 118 substantially similar to via 66 is included
within the means of cable interposer 111 for connecting each second
connector pad 57 to the electrical trace 117 of the respective first
connector pad 112.
Connector assembly 109 has a rigid printed circuit board 122 which is
substantially identical to rigid printed circuit board 22 except that
first interconnect pads 123 of the rigid printed circuit board 122 are
offset relative to first interconnect pads 27 of rigid printed circuit
board 22 by an amount equal to the offset of first connector pads 112
relative to second connector pads 57. As such, first interconnect pads 123
ofthe rigid printed circuit board 22 are offset with respect to second
interconnect pads 42 of flexible printed circuit cable 34. It should be
appreciated that cable interposer 111 can be utilized with any combination
of flexible and/or rigid printed circuit board so long as a first and
second interconnect pads of such boards are offset in the manner that
first connector pads 112 of the cable interposer are offset with respect
to second connector pads 57.
In operation and use, connector assembly 109 is assembled in the same
manner as discussed above with respect to connector assembly 21. The first
connector pads 112 are pivotable by means of flexible sheet 52 of cable
interposer 111 with respect to second connector pads 57 for enhancing
electrical connections between first interconnect pads 123 and second
interconnect pads 42. In this manner, cable interposer 111 can further
accommodate irregularities in the thicknesses of either rigid printed
circuit board 122 or flexible printed circuit cable 34 or discrepancies in
the thicknesses of first interconnect pads 123 or in the thicknesses of
second interconnect pads 42.
From the foregoing, it can be seen that a high density electrical connector
assembly having a small footprint has been provided. The connector
assembly does not utilize soldered connections and can be easily
disassembled and reassembled. The connector assembly preferably has a
plurality of interconnect and connector pads which can be of any suitable
size and shape and arranged in any suitable pattern. A reusable and
compliant interposer for disposition between first and second printed
circuit boards is included in the connector assembly.
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